Eagle Nebula - Amazing Space
... radiation heats the surrounding gas, making it glow. This intense radiation is responsible for sculpting the columns; it erodes more tenuous gas in the columns through a process called photoevaporation. The erosion reveals denser gas globules surrounding newly formed stars (see close-up, right). Sci ...
... radiation heats the surrounding gas, making it glow. This intense radiation is responsible for sculpting the columns; it erodes more tenuous gas in the columns through a process called photoevaporation. The erosion reveals denser gas globules surrounding newly formed stars (see close-up, right). Sci ...
Powerpoint
... Stars form out of molecular gas (dust) clouds. Star formation happens when part of a dust cloud begins to contract under its own gravitational force (remember, stars are ~1020 x denser than a molecular cloud). As it collapses, the center becomes hotter and hotter until nuclear fusion begins in the c ...
... Stars form out of molecular gas (dust) clouds. Star formation happens when part of a dust cloud begins to contract under its own gravitational force (remember, stars are ~1020 x denser than a molecular cloud). As it collapses, the center becomes hotter and hotter until nuclear fusion begins in the c ...
Determining the Sizes & Distances of Stars Using the H
... cores, but after awhile they evolve and begin to die. How long they live and what they evolve to become when they die depends on their mass. In fact, the mass of a star also determines its most important properties: its luminosity, temperature and radius. A star's luminosity, which is how much energ ...
... cores, but after awhile they evolve and begin to die. How long they live and what they evolve to become when they die depends on their mass. In fact, the mass of a star also determines its most important properties: its luminosity, temperature and radius. A star's luminosity, which is how much energ ...
ASTR-1020: Astronomy II Course Lecture Notes - Faculty
... We know this since one solar mass stars should last on the main sequence (see §III.C.) for 10 billion years and the Sun is currently 5 billion years old. As such, we have 5 billion more years before the Sun becomes a red giant, at which such time, it will “swallow” the most of the inner planets of t ...
... We know this since one solar mass stars should last on the main sequence (see §III.C.) for 10 billion years and the Sun is currently 5 billion years old. As such, we have 5 billion more years before the Sun becomes a red giant, at which such time, it will “swallow” the most of the inner planets of t ...
Solar Lithium Mystery Solved
... conducted a survey of 500 stars, nearly 25% of which are like our own sun (Nature 2009, 462, 189). Seventy of the sunlike stars are known to have planetary systems. Most of the stars that host planets have on average one-tenth the amount of lithium of sunlike stars without planets. The researchers s ...
... conducted a survey of 500 stars, nearly 25% of which are like our own sun (Nature 2009, 462, 189). Seventy of the sunlike stars are known to have planetary systems. Most of the stars that host planets have on average one-tenth the amount of lithium of sunlike stars without planets. The researchers s ...
Integrative Studies 410 Our Place in the Universe
... distance ladder out as far as we can see Cepheids – about 50 million ly • In 1920 Hubble used this technique to measure the distance to Andromeda (about 2 million ly) • Works best for periodic variables ...
... distance ladder out as far as we can see Cepheids – about 50 million ly • In 1920 Hubble used this technique to measure the distance to Andromeda (about 2 million ly) • Works best for periodic variables ...
1b91: answers to problem sheet no 1
... (b) Briefly explain why the more massive a star is, the shorter its lifetime. The band called the main sequence in the H-R diagram runs diagonally from hot, luminous blue stars in the upper left hand corner to cool, red, faint stars in the lower right hand corner. It represents the part of a star’s ...
... (b) Briefly explain why the more massive a star is, the shorter its lifetime. The band called the main sequence in the H-R diagram runs diagonally from hot, luminous blue stars in the upper left hand corner to cool, red, faint stars in the lower right hand corner. It represents the part of a star’s ...
Rotation
... the star. E.g., CN processing, s-process, He, etc. 2) Structurally, the helium and heavy element core – once its mass has been determined is insensitive to the presence of the envelope. If the entire envelope is lost however, the star enters a phase of rapid Wolf-Rayet mass loss that does greatly af ...
... the star. E.g., CN processing, s-process, He, etc. 2) Structurally, the helium and heavy element core – once its mass has been determined is insensitive to the presence of the envelope. If the entire envelope is lost however, the star enters a phase of rapid Wolf-Rayet mass loss that does greatly af ...
Notes 14-2
... The size of the Sun • If the Sun were a hollow ball more then a million Earths could fit inside it! • The Sun is an average size star and the largest object in the solar system. • The Sun looks larger than the other stars that can be seen in the night sky because it is much closer to Earth. ...
... The size of the Sun • If the Sun were a hollow ball more then a million Earths could fit inside it! • The Sun is an average size star and the largest object in the solar system. • The Sun looks larger than the other stars that can be seen in the night sky because it is much closer to Earth. ...
1 How luminous are stars?
... We measure mass using gravity Direct mass measurements are possible only for stars in binary star systems ...
... We measure mass using gravity Direct mass measurements are possible only for stars in binary star systems ...
The Life Cycles of Stars
... Black Holes- Black holes are another resulting body created after a supernova, usually having to be greater than at least 3.0 solar masses. When a star collapses at such a size, the stellar object becomes incredibly small and dense, resulting in a gravitational pull so powerful that radiation (heat) ...
... Black Holes- Black holes are another resulting body created after a supernova, usually having to be greater than at least 3.0 solar masses. When a star collapses at such a size, the stellar object becomes incredibly small and dense, resulting in a gravitational pull so powerful that radiation (heat) ...
MIDTERM #2 THURSDAY APRIL 16, 2015 AST142 1. Black hole
... MIDTERM #2 THURSDAY APRIL 16, 2015 AST142 ...
... MIDTERM #2 THURSDAY APRIL 16, 2015 AST142 ...
Document
... Globular clusters in only one direction. Globular clusters in all directions. Many more supernovae than we do now. Many more stars being formed than we do now. None of the above. ...
... Globular clusters in only one direction. Globular clusters in all directions. Many more supernovae than we do now. Many more stars being formed than we do now. None of the above. ...
Where Do Chemical Elements Come From?
... More on the life cycle of stars In order for students to understand the origin of the elements, they should also have an understanding of basic concepts that might be covered in an advanced astronomy course. The processes that produce the chemical elements are an integral part of the life cycle of s ...
... More on the life cycle of stars In order for students to understand the origin of the elements, they should also have an understanding of basic concepts that might be covered in an advanced astronomy course. The processes that produce the chemical elements are an integral part of the life cycle of s ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.